U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This report is an archived publication and may contain dated technical, contact, and link information |
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Publication Number: FHWA-HRT-05-053 Date: September 2005 |
If the concrete pavement industry continues to use the same types of materials, the same problems and limitations will persist in concrete pavement applications. Fortunately, innovative concrete paving materials continually are being developed to enhance performance, improve construction, and reduce waste. The problem statements in this track will develop new materials and refine or introduce existing advanced materials. Many existing materials that the problem statements study have been used thus far only on a small scale, such as in laboratory tests. Most existing materials have not been used in the United States, but have been used successfully in other countries. This track will bring new concrete paving materials into common practice by experimenting with them on a larger scale and developing standards and recommendations for their use. Moreover, this research will foster innovation in the development of new and innovative concrete pavement materials.
The problem statements in this track are grouped into three subtracks: performance-enhancing, construction-enhancing, and environment-enhancing concrete pavement materials. Performanceenhancing materials will improve pavement durability and long-term performance, perhaps extending pavement life further than conventional materials. Construction-enhancing materials will improve the construction process by reducing material requirements, labor requirements, or construction time. Finally, environment-enhancing materials show promise not only by reducing waste through pavement reclamation, but also for reducing raw consumer and industrial waste. Clearly, many of these materials fit into more than one category. A material that improves the construction process, for example, also may improve pavement durability and performance. Likewise, a material that uses consumer waste also may improve pavement performance.
The emphasis on environment-enhancing materials is significant. Not only are contractors and agencies paying heavily to dispose of reclaimed asphalt and concrete pavement, but also other industries are looking for environmentally responsible ways to dispose of industrial and consumer waste to reduce the burden on landfills. Environmental concerns are expected to become more important in the next few decades as landfills quickly fill.
The following introductory material summarizes the goal and objectives for this track and the gaps and challenges for its research program. A chart is included to show an overview of the subtracks and problem statements in the track. A table of estimated costs provides the projected cost range for each problem statement, depending on the research priorities and scope determined in implementation. The problem statements, grouped into subtracks, follow.
New materials will be evaluated and existing materials will be refined to improve concrete pavement performance, enhance construction, and lessen environmental impact.
The horizontal bar chart in figure 12 shows the problem statements in this track grouped by subtrack. Because this track is unphased, no time phasing is shown.
Click to enlarge or view alternative text
Figure 12. Track 12 (AM) unphased subtrack and problem statement chart.
Table 58 shows the estimated costs for this research track.
Problem Statement | Estimated Cost |
---|---|
Subtrack AM 1. Performance-Enhancing Concrete Pavement Materials | |
AM 1.1. Flexible Cementitious Overlay Materials | $500 k-$1 M |
AM 1.2. High-Performance, Fiber-Reinforced Concrete Pavements | $1 m-$2 M |
AM 1.3. Pervious Concrete Pavement Program | $500 k-$1 M |
AM 1.4. Carbon Dioxide-Treated Materials | $100 k-$250 k |
AM 1.5. Reactive Powder Concretes as Ductile Materials | $500 k-$1 m |
AM 1.6. Chemically Bonded Ceramic | $100 k-$250 k |
AM 1.7. Localized High-Quality Concrete at the Joints | $1 M-$2 M |
AM 1.8. Alternative Reinforcement Material for Continuously Reinforced Concrete Pavements | $500 k-$1 M |
Subtrack AM 2. Construction-Enhancing Concrete Pavement Materials | |
AM 2.1. Application of Self-Consolidating Concrete for Concrete Paving | $500 k-$1 M |
AM 2.2. Applying Very High-Strength Concrete to Pavement Operations | $1 M-$2 M |
AM 2.3. Dry-Laid Concrete | $500 k-$1 M |
AM 2.4. Energetically Modified Cement | $100 k-$250 k |
AM 2.5. Advanced Curing Materials | $250 k-$500 k |
AM 2.6. Cold Weather Concreting Advancements | $500 k-$1 M |
AM 2.7. Advancements in Internal Curing of Concrete | $250 k-$500 k |
AM 2.8. Self-Curing Concrete | $250 k-$500 k |
Subtrack AM 3. Environment-Enhancing Concrete Pavement Materials | |
AM 3.1. Cement Containing Titanium Dioxide | $100 k-$250 k |
AM 3.2. Sulfur Concrete | $100 k-$250 k |
AM 3.3. Increased Percentages of Reclaimed Asphalt Pavement as an aggregate for Concrete Paving Mixtures | $1 M-$2 M |
AM 3.4. Mix Design Considerations with Recycled Concrete Aggregate | $1 M-$2 M |
AM 3.5. Acceptance Criteria for Using Recycled Aggregate | $500 k-$1 M |
AM 3.6. Waste Materials in Concrete Mixes | $1M-2 M |
AM 3.7. Ecocement for Concrete Mixes | $100k-250 k |
AM 3.8. Polymer Concrete Made from Recycled Plastic Bottles | $100k-250 k |
Track 12 (AM) | |
Total | $11.45 M-$23.25 M |
Track 12 (AM) problem statements are grouped into three subtracks:
Each subtrack is introduced by a brief summary of the subtrack’s focus and a table listing the titles, estimated costs, products, and benefits of each problem statement in the subtrack. The problem statements follow.
The innovative materials developed in this subtrack may meet requirements that conventional concretes do not meet as efficiently. The materials developed are specialty concrete varieties for specific, unique applications. Table 59 provides an overview of this subtrack.
Problem Statement | Estimated Cost | Products | Benefits |
---|---|---|---|
AM 1.1. Flexible Cementitious Overlay Materials | $500 k-$1 M | Specifications, design criteria, and construction procedures for flexible cementitious overlays. | New, more durable overlay material that is less susceptible to rutting and shoving than asphalt and can be placed in thin, flexible layers. |
AM 1.2. High-Performance, Fiber-Reinforced Concrete Pavements | $1 M-$2 M | Design recommendations, construction procedures, and specifications for fiber-reinforced concrete pavement. | Fiber reinforcement that will result in highperformance concrete pavement that is less susceptible to microcracking from concrete shrinkage than other pavements, resulting in a more durable, long-lasting pavement. |
AM 1.3. Pervious Concrete Pavement Program | $500 k-$1 M | Design recommendations, construction procedures, and specifications for pervious concrete pavement for highways. | Pervious concrete pavements that will drain water from the pavement surface without the need for a cross slope, improving the safety of the pavement surface; promotion of the breakdown of chemical pollutants due to the large surface area within the pavement surface. |
AM 1.4. Carbon Dioxide-Treated Materials | $100 k-$250 k | Recommendations for using carbon dioxide-treated materials for concrete pavements. | Carbon dioxide-treated materials that will increase strength and the rate of strength development, while significantly decreasing permeability, resulting in more durable pavements that can be opened to traffic faster. |
AM 1.5. Reactive Powder Concretes as Ductile Materials | $500 k-$1 M | Design and material recommendations and construction procedures for using reactive powder concrete (RPC) for ultrahigh-performance concrete pavements. | Ultrahigh-performance concretes using RPC that are very high-strength concretes with ductility and very low permeability; the possibility of thinner pavement sections and reduced or eliminated reinforcement, resulting in a more durable pavement that is cheaper to construct. |
AM 1.6. Chemically Bonded Ceramic | $100 k-$250 k | Recommendations for using Ceramicrete in concrete paving applications. | Better corrosion resistance and strength characteristics for concrete pavements, resulting from Ceramicrete’s very low permeability and higher compressive strength than normalstrength concrete. |
AM 1.7. Localized High-Quality Concrete at the Joints | $1 M-$2 M | Recommendations for using highquality materials at the joints in concrete pavements. | High-quality material at the joint regions in concrete pavements that may not be affordable for use in the rest of the slab, ensuring better joint toughness and durability and enhancing pavement life. |
AM 1.8. Alternative Reinforcement Material for Continuously Reinforced Concrete Pavements | $500 k-$1 M | Recommendations for alternative reinforcing materials for CRCP. | Alternative reinforcing materials that provide better corrosion resistance, bond strength, and modulus of elasticity; lighter materials that reduce labor costs during placement and dependence on a volatile steel market. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
The majority of HMA pavements ultimately will fail due to rutting. Increased axle loads, higher tire pressures, and increasing traffic volume contribute to this problem; today, more than 90 percent of roads are being overloaded. Developing a cementitious overlay material that can be used as a strengthening and wearing course on flexible pavements, even when applied in thin layers, would be extremely useful. Ductility of the material is obtained through controlled microcracking and fiber reinforcement. A major project is currently underway in the European Union to look at porous polymer concretes. Several different compositions such as this could be used, resulting in the selection of a few types to be used for full-scale testing as overlays on appropriate highways. A similar project could be conducted in the United States that builds on the information and results from the European Union project. Design criteria and draft specifications for the use of the new material will be a part of the project results.
Tasks:
Benefits: | New, more durable overlay material that is less susceptible to rutting and shoving than asphalt and can be placed in thin, flexible layers. |
Products: | Specifications, design criteria, and construction procedures for flexible cementitious overlays. |
Implementation: | This project will result in draft specifications, design criteria, and construction procedures for flexible cementitious overlays. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
In recent years, advancements have been made regarding the use of fiber reinforcement for improving concrete pavement performance. The first goal of this project will be to synthesize the information available about this topic. Researchers then could determine the potential of advanced fiber concepts aimed at extending the long life pavement category. Attention should be given to both the benefits and drawbacks of using fiber reinforcement. The end product would include both procedural and analytical guidance for the optimum use of fibers. It is anticipated that this research will explore the field of fracture mechanics and will improve understanding of the impacts that fibers can play on load transfer (as compared to dowels and tie bars).
Tasks:
Benefits: | Fiber reinforcement that will result in high-performance concrete pavement that is less susceptible to microcracking from concrete shrinkage than other pavements, resulting in a more durable, long-lasting pavement. |
Products: | Design recommendations, construction procedures, and specifications for fiberreinforced concrete pavement. |
Implementation: | This project will result in design recommendations, construction procedures, and specifications for fiber-reinforced, high-performance concrete pavement. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
Pervious or porous concrete pavement has several notable advantages over conventional concrete pavement, primarily noise reduction and better drainage. Certain types of pervious pavement can pass 11.4 to 18.9 liters (3 to 5 gallons) of water per minute, which is much greater than most conceivable rain events and very effective in reducing hydroplaning risk. Porous concrete also offers improved filtration and an enormous amount of surface area to catch oils and chemical pollutants, which can reduce skid and environmental damage. Some experts believe that the bacteria living in these spaces breakdown pollutants, preventing much of the runoff pollution that normally occurs with traditional pavements. Most of the pervious pavements constructed thus far, however, have been for parking lots, not highways. This research would investigate the use of pervious concrete in highway pavements, examining the advantages and disadvantages, including the feasibility of large-scale pavement construction. The study should examine long-term maintenance and durability issues, such as permeability, abrasion resistance, and wetting/drying, as well as the effect of the bacteria. Stages of this research would include the development of mix design techniques as well as the field trial phase.
Tasks:
Benefits: | Pervious concrete pavements that will drain water from the pavement surface without the need for a cross slope, improving the safety of the pavement surface; promotion of the breakdown of chemical pollutants due to the large surface area within the pavement surface. |
Products: | Design recommendations, construction procedures, and specifications for pervious concrete pavement for highway pavements. |
Implementation: | This project will result in design recommendations, construction procedures, and specifications for using pervious concrete for highway pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
The treatment of cementitious materials with gaseous carbon dioxide to achieve rapid strength development has been studied for many years. Recently, advances have been made in the treatment of cementitious materials that will facilitate the use of supercritical carbon dioxide in achieving a tenfold reduction in permeability, while strength increases by several fold. While the precast concrete industry already uses this technology, further research is needed to apply the technology to pavements. In particular, research is needed to better understand the mechanisms of rapid strength development in concrete with supplementary cementitious materials. With further research, this process likely could lead to the development of new materials from novel waste streams and accelerate the development of new and improved concrete mixtures.
Tasks:
Benefits: | Carbon dioxide-treated materials that will increase strength and the rate of strength development, while significantly decreasing permeability, resulting in more durable pavements that can be opened to traffic faster. |
Products: | Recommendations for using carbon dioxide-treated materials for concrete pavements. |
Implementation: | This project will result in recommendations for using carbon dioxide-treated materials for concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
With a technological breakthrough at the beginning of the 1990s, RPC offered compression strengths in excess of 200 megapascals (MPa) (29,000 pounds-force per square inch (psi)), flexural strengths of over 40 MPa (5,800 psi), and ductility. Ductal® and BSI®, two products of the RPC family developed in France, are considered ultrahigh-performance concretes. They are ductile materials capable of resisting substantial flexural loads and do not require passive reinforcement. This allows the overall thickness of structural elements to be reduced. The material is also extremely durable with very low permeability. Thus far, this material has been used predominantly in Europe for concrete structures, but future research should investigate its use in concrete pavements with or without fibers.
Tasks:
Benefits: | Ultrahigh-performance concretes using RPC that are very high-strength concretes with ductility and very low permeability; the possibility of thinner pavement sections and a reduction or elimination of reinforcement, resulting in a more durable pavement that is cheaper to construct. |
Products: | Design and material recommendations and construction procedures for using RPC for ultrahigh-performance concrete pavements. |
Implementation: | This project will result in design and material recommendations, specifications, and construction procedures for using RPC to achieve ultrahigh-performance concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
Chemically bonded phosphate ceramic (Ceramicrete) is a type of concrete with very low permeability. Ceramicrete is formed when magnesium oxide powder and soluble phosphate powder (both available, low-cost materials) are mixed with water, creating a nonporous material with compressive strength higher than that of concrete. Ceramicrete can be made with commercially available equipment that mixes the powder components into the binder. "The wet material (binder, aggregates, and water mixture) can then be pumped, gunned, or sprayed, also with commercially available equipment."(6) The feasibility (costs and benefits) of using Ceramicrete for concrete paving should be explored.
Tasks:
Benefits: | Better corrosion resistance and strength characteristics for concrete pavements, resulting from Ceramicrete’s very low permeability and higher compressive strength than normal strength concrete. |
Products: | Recommendations for the use of Ceramicrete for concrete paving applications. |
Implementation: | This project will result in recommendations for the use of Ceramicrete for concrete paving applications, including repairs, overlays, and new construction. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
Many concrete pavement failures occur because of joint damage. Improving the quality of the concrete at these potential weak areas thus would increase the overall pavement life. Therefore, a system should be developed to ensure that the concrete at the joints consists of a higher quality material than the concrete midslab. This process could involve introducing fibers, chemicals, or other additives at the joints.
Tasks:
Benefits: | High-quality material at the joint regions in concrete pavements that may not be affordable for use in the rest of the slab, ensuring better joint toughness and durability and enhancing pavement life. |
Products: | Recommendations for using high-quality materials at the joints in concrete pavements. |
Implementation: | This project will result in design construction recommendations for using highquality materials at the joints in concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 1. Performance-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
Steel reinforcement is a critical component of CRCP. However, factors such as concrete permeability and water infiltration at cracks, the resulting corrosion of steel reinforcement, and the associated tendency of concrete to lose bond action with imbedded reinforcement reduce structural performance over time. Research is needed to develop economical, thermodynamically durable, metallic and nonmetallic corrosion-resistant reinforcements. Widespread use of these technologies, which have been researched for many years, will lead to additional refinements, such as the further development of fiber-reinforced plastic (FRP) bars with a useful form of pseudo-ductility that makes full use of their strength. Another advantage of alternate reinforcing materials for CRCP is reduced placement costs. Lightweight FRP bars require less labor to be installed. Researchers should begin by examining work that has been done previously in this area, including ongoing studies sponsored by FHWA.
Tasks:
Benefits: | Alternative reinforcing materials that provide better corrosion resistance, bond strength, and modulus of elasticity; lighter materials that reduce labor costs during placement and dependence upon a volatile steel market. |
Products: | Recommendations for alternative reinforcing materials for CRCP. |
Implementation: | This project will result in recommendations for the design and use of alternative reinforcing materials for CRCP. |
The materials developed under this subtrack address specific constructability issues and provide creative alternatives to conventional concrete. The problem statements in this subtrack will develop special concrete materials for use in various concrete paving applications. Table 60 provides an overview of this subtrack.
Problem Statement | Estimated Cost | Products | Benefits |
---|---|---|---|
AM 2.1. Application of Self-Consolidating Concrete for Concrete Paving | $500 k-$1 M | Recommendations for design and construction of pavements using self-consolidating concrete (SCC). | Better consolidation of concrete around dowels and reinforcement, reducing the need for vibration, resulting in a more durable pavement while reducing labor costs during construction. |
AM 2.2. Applying Very High-Strength Concrete to Pavement Operations | $1 M-$2 M | Mix design recommendations, construction procedures, and specifications for very highstrength concrete pavements. | Concrete pavement with a very high tensile strength to permit longer sections of pavement to be constructed, reducing the number of joints, and helping to reduce cracking and improve long-term durability. |
AM 2.3. Dry-Laid Concrete | $500 k-$1 M | Design and construction guidelines and recommendations for dry-laid concrete pavement. | Dry-laid concrete pavement that eliminates the need for mixing concrete onsite (batch-plants) and permits thinner, durable pavement slabs, greatly reducing construction and materials costs. |
AM 2.4. Energetically Modified Cement | $100 k-$250 k | Recommendations for the use of energetically modified cement (EMC) for concrete paving mixes. | EMC with faster strength development and better long-term strength of blended mixes, resulting in more durable pavements using blended mixes that can be opened to traffic sooner. |
AM 2.5. Advanced Curing Materials | $250 k-$500 k | Recommendations for advanced curing materials and the requirements for these materials. | More effective curing materials for concrete paving operations, especially those constructed under short construction windows and in extreme environments; advanced curing materials that better ensure the necessary curing requirements, resulting in a more durable pavement. |
AM 2.6. Cold Weather Concreting Advancements | $500 k-$1 M | Recommendations for cold weather paving mixes and construction practices. | Cold weather-tolerant concrete paving mixes and construction techniques that will extend the pavement construction season in colder regions and reduce the labor required to protect pavements during cold weather paving operations. |
AM 2.7. Advancements in Internal Curing of Concrete | $250 k-$500k | Mix design recommendations that will promote internal curing (IC) of concrete pavements. | IC that will help reduce autogenous shrinkage and self-desiccation and will ensure more complete hydration of cementitious materials, resulting in a less permeable, stronger, more durable pavement. |
AM 2.8. Self-Curing Concrete | $250 k-$500 k | Recommendations on materials and techniques for constructing self-curing concrete pavements. | Self-curing concrete pavements that will reduce dependence on the contractor to apply adequate curing measures to new concrete pavement; more complete hydration of the cementitious materials, resulting in stronger, less permeable, and more durable concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
Significant interest in recent years has arisen over the use of SCC for various applications. The most common application is in complex structural work, where the presence of the reinforcing steel has made adequate consolidation using conventional means difficult. Because some concrete paving work faces similar challenges with consolidation (near dowels and reinforcements), using SCC for concrete paving has been suggested. As part of this effort, researchers will evaluate innovative ways to incorporate SCC into PCC pavements that include full sections, overlays, inlays, and patching, for both fixed- and slipform operations. This research will build on work already underway by FHWA and other organizations.
Tasks:
Benefits: | Better consolidation of concrete around dowels and reinforcement, reducing the need for vibration, resulting in a more durable pavement while reducing labor costs during construction. |
Products: | Recommendations for design and construction of pavements using SCC. |
Implementation: | This project will result in design recommendations and best practice construction procedures for using SCC for pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
High-strength concrete currently is being used in rapid-cure patches. However, the high cement content causes high temperatures that can result in thermal contraction problems. At present, early opening is the only advantage to using high-strength concrete in pavements. Also, such concrete is expensive, and if high-strength pavements are to be competitive, ways to minimize the amount of the expensive concrete must be found. The French have developed a two-layer extruded slipform operation that encapsulates normal concrete within a protective high-strength concrete. Other more economical options also might be considered, such as slabs cast with internal voids, or beam and slab configurations, although data is needed on deflection, water movement, friction, curling, and warping of unusual slab configurations. Jointing technology also would be needed. A vigorous research study would be needed to make using 69 MPa (10,000 psi) concrete more efficient for structural pavements.
Just as continuously welded rails are used, it should be possible to construct a continuous ribbon of concrete that would withstand a temperature range of 55 °C (100 °F). A tensile strength of about 17 MPa (2,500 psi) would be needed, which might be possible with a compressive strength of about 172 MPa (25,000 psi) (plus a factor of safety). This could be accomplished with polymer impregnation if a field process could be developed. For comparison, a laboratory strength of about 731 MPa (106,000 psi) has been attained with PCC. Special concretes currently are being used in the 172 MPa (25,000 psi) range, based on a reactive powder process. The strength must be attained about 18 hours before the concrete begins to cool and contract. Of course, such continuous ribbons of ultrahigh-strength concretes will experience about 50 mm (2 inches) of movement at the ends, making special anchors or joints necessary.
Tasks:
Benefits: | Concrete pavement with a very high tensile strength to permit longer sections of pavement to be constructed, reducing the number of joints, and helping to reduce cracking and improve long-term durability. |
Products: | Mix design recommendations, construction procedures, and specifications for very high-strength concrete pavements. |
Implementation: | This project will result in mix design recommendations, construction procedures, and specifications for high-strength concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
New formulations and procedures have been developed that enable concrete to be placed as a cementitious dry mix that is then watered from above to produce a strong, thin slab or pavement. The need for onsite mixing is eliminated. In the field, the strength of dry-laid slabs only 10 to 50 mm (0.39 to 1.95 inches) thick saves raw materials and excavation costs and may make resurfacing old concrete a practical possibility. Dry-laid materials are also easier to work with than conventional moist or semidry concrete screeds, and should result in a stronger and more durable end product.
Preliminary tests indicate that strong concrete substantially free of shrinkage cracking can be produced by dry-laid methods using premixed materials in which the maximum particle size is limited, typically to 5 mm (0.2 inch) in diameter. The absence of large particles means that thinner slabs of concrete down to 10 mm (0.39 inch) can be laid. Although the mixture has a higher cement and fines content than conventional concrete, the dry-laid process reduces the problem of self-induced cracking due to drying shrinkage that generally is encountered with cement-rich mortars laid as a wet mix. Although the product originally was conceived as an easy-to-use, do-it-yourself surfacing product, there appears to be a major opportunity to apply it to concrete paving. Innovative aspects of dry-laid techniques include:
Tasks:
Benefits: | Dry-laid concrete pavement that eliminates the need for mixing concrete onsite (batch-plants) and permits thinner, durable pavement slabs, greatly reducing construction and materials costs. |
Products: | Design and construction guidelines and recommendations for dry-laid concrete pavement. |
Implementation: | This project will result in recommendations for using dry-laid concrete for PCC pavements, including design guidelines and construction procedures. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
One important constraint of using cement blended with various pozzolanic or cementitious substances (e.g., fly ash, blast furnace slag) is the early strength development requirements included in current standards. Blended cements typically take longer to develop their strength and often do not meet standards without additives. EMC is a patented technology that has overcome this obstacle. By intensively grinding and activating the cement together with the pozzolan, the surfaces of the particles are activated. Investigators believe that the activation creates a network in the cement particles of submicrocracks, microdefects, and dislocations that allows the water to penetrate deeper into the cement particles, which in turn uses a higher percentage of the potential binding capacity of the cement. This process also activates inert fillers, such as fine quartz sand. The EMC technology is based solely on grinding; no additives of any kind are used. Evaluations and tests of concretes and mortars made with EMC have shown EMC to perform significantly better than portland pozzolan-blended cements containing 20-40 percent fly ash. EMC with fly ash, by comparison, allows a 10 percent reduction in water-cement ratio, translating to higher long-term strength. EMC also showed slightly improved sulfate resistance, and the workability of EMC was better than cement.
Tasks:
Benefits: | EMC with faster strength development and better long-term strength of blended mixes, resulting in more durable pavements using blended mixes that can be opened to traffic sooner. |
Products: | Recommendations for the use of EMC for concrete paving mixes. |
Implementation: | This project will result in recommendations for the use of EMC for concrete paving mixes. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $250 k-$500 k |
Curing methods used for concrete paving have not changed significantly in the past 30 years. Liquid curing compound remains the most commonly used form of protection. However, the demands being placed on concrete paving are evolving. Rapid reconstruction and extreme weather events have challenged traditional curing methods and demand better solutions. This project will investigate new and advanced curing materials for these extreme circumstances. Effectiveness, cost, and proprietary issues should be considered. Ideally, the project will result in a performance or end-result standard for advanced curing materials that would allow adequate competition and provide the user with the desired properties. To further this goal, a functional specification could be developed that establishes critical moisture and temperature conditions required to achieve varying degrees of quality. The ability of the cure to meet these functional thresholds would determine its quality.
Tasks:
Benefits: | More effective curing materials for concrete paving operations, especially those constructed under short construction windows and in extreme environments; dvanced curing materials that better ensure the necessary curing requirements, resulting in a more durable pavement. |
Products: | Recommendations for advanced curing materials and the requirements for these materials. |
Implementation: | This project will result in recommendations for different types of advanced curing materials and requirements for the effectiveness of these materials. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
USACE researchers are experimenting with concrete admixtures that allow for subzero pours as low as -15 °C (5 °F) in the open air. Underwritten by 10 State DOTs, the 3-year, $750,000 program is paving the way for reduced labor in winter months and a longer construction season. The team is working with combinations of off-the-shelf products to lower the freezing temperature of concrete. These substances, which commonly are available to contractors, include concrete accelerators, corrosion inhibitors, and plasticizers already governed by their own set of standards. One recent study involved a 32-m (104-ft)- long bridge curb in Lebanon, NH. The result of using the laboratory’s experimental concrete was a savings of 132 labor hours needed to build an enclosure and $50 in liquid propane. The total cost was $700, rather than $750 plus labor for traditional methods. The next step is to develop a recipe guide for admixture chemicals. Beyond this, research still is needed to demonstrate the benefits of this technology for concrete pavements.
Tasks:
Benefits: | Cold weather-tolerant concrete paving mixes and construction techniques that will extend the pavement construction season in colder regions and reduce the labor required to protect pavements during cold weather paving operations. |
Products: | Recommendations for cold weather paving mixes and construction practices. |
Implementation: | This project will result in recommendations for cold weather concrete paving mixes and construction practices. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $250 k-$500 k |
In the past few years, IC has evolved into a science. With the advent of lower water-cement ratio mixtures and high-performance concrete, the need for a system to eliminate autogenous shrinkage and selfdesiccation has developed, and the use of lightweight fines for the IC of concrete increasingly is being recognized. The paper, "Internal Curing of Concrete Using Lightweight Aggregate" includes a state of the art of practice in this area.(7) In this research, the use of IC for concrete pavement will be explored. The costs and benefits of this technology should be weighed and a recommendation made for proceeding with field trials and other implementation projects.
Tasks:
Benefits: | IC that will help reduce autogenous shrinkage and self-desiccation and will ensure more complete hydration of cementitious materials, resulting in a less permeable, stronger, more durable pavement. |
Products: | Mix design recommendations that will promote IC of concrete pavements. |
Implementation: | This project will result in material and mix design recommendations that will promote IC of concrete pavements. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 2. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $250 k-$500 k |
Most paving mixtures contain adequate mixing water to hydrate the cement if the moisture is not allowed to evaporate. It should be possible to develop an oil, polymer, or other compound that would rise to the finished concrete surface and effectively seal the surface against evaporation. R.K. Dhir et al. recently published some test results on self-curing mixtures.(8) This research will explore further the potential of self-curing concrete.
Tasks:
Benefits: | Self-curing concrete pavements that will reduce dependence on the contractor to apply adequate curing measures to new concrete pavement; more complete hydration of the cementitious materials, resulting in stronger, less permeable, and more durable concrete pavements. |
Products: | Recommendations on materials and techniques for constructing self-curing concrete pavements. |
Implementation: | This project will result in recommendations on materials and techniques for constructing self-curing concrete pavements. |
The problem statements in this subtrack will address environmental concerns in concrete pavement materials, construction, and performance. The materials developed in this research can be used to improve air quality and will enhance recycled concrete pavement materials. Table 61 provides an overview of this subtrack.
Problem Statement | Estimated Cost | Products | Benefits |
---|---|---|---|
AM 3.1. Cement Containing Titanium Dioxide | $100 k-$250 k | Recommendations for the use of cement containing titanium dioxide in concrete paving mixes. | Concrete pavements containing titanium dioxide that potentially can remove certain volatile organic compounds (VOC) from the air, helping to reduce air pollution in urban areas. |
AM 3.2. Sulfur Concrete | $100 k-$250 k | Recommendations for the use of sulfur concrete in paving applications. | Sulfur concrete that consists of 100 percent recycled material, made from byproducts of electricity production and petroleum refinement; a dense, acid-resistant material that may have applications for concrete paving. |
AM 3.3. Increased Percentages of Reclaimed Asphalt Pavement as an Aggregate for Concrete Paving Mixtures | $1 M-$2 M | Recommendations for using reclaimed asphalt pavement (RAP) as an aggregate for concrete paving mixes. | RAP in concrete paving mixes, reducing the amount of RAP that must be disposed, as well as reducing the demand for virgin aggregate for concrete pavements. |
AM 3.4. Mix Design Considerations with Recycled Concrete Aggregate | $1 M-$2 M | Recommendations for using recycled concrete as aggregate in new pavement construction. | Recycled concrete for aggregate in new concrete pavements, reducing the amount of reclaimed concrete pavement that must be disposed, as well as the demand for virgin aggregate in concrete pavements. |
AM 3.5. Acceptance Criteria for using Recycled Aggregate | $500 k-$1 M | Recommendations for acceptance criteria and test procedures for recycled aggregate and concrete made with recycled aggregate. | Established acceptance criteria and test procedures for recycled aggregate in new concrete pavements to promote the use of recycled aggregates, thereby reducing the demand for virgin aggregate for new construction. |
AM 3.6. Waste Materials in Concrete Mixes | $1 M-2 M | Recommendations (proportions and limits) for the use of waste materials in concrete paving mixes. | Use of waste materials in concrete mixes, reducing the amount of waste materials and the demand for cement (which must be produced), while producing a better concrete mix. |
AM 3.7. Ecocement for Concrete Mixes | $100 k-250 k | Recommendations for the production and use of Ecocement in the United States. | Ecocement that is produced during the incineration of solid waste and sewage sludge, reducing the amount of waste, while reducing the amount of cement required for concrete paving mixes, resulting in a faster setting concrete mix. |
AM 3.8. Polymer Concrete Made from Recycled Plastic Bottles | $100 k-250 k | Recommendations for using polymer concrete for paving applications. | Polymer concrete that results in a more durable pavement or pavement overlay, making use of recycled plastic bottles and reducing the demand on landfills. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
To help reduce air pollution and prevent the discoloration of urban concrete surfaces, several cement companies have marketed cement containing a photocatalyst (titanium dioxide), which removes polluting VOCs from the atmosphere and converts them to carbon dioxide. If put into widespread use, such cement could potentially improve urban air quality (e.g., reduce smog), since the amount of carbon dioxide produced would be much smaller than the amount of carbon dioxide from combustion sources. The use of cementitious materials containing photocatalysts is thus an innovative and profitable way to eliminate pollutants, particularly in urban areas. Concrete pavement would be an ideal application for such a product, as the pavement could decrease the smog produced by the vehicles traveling over the pavement.
Tasks:
Benefits: | Concrete pavements containing titanium dioxide that can potentially remove certain VOCs from the air, helping reduce air pollution in urban areas. |
Products: | Recommendations for the use of cement containing titanium dioxide in concrete paving mixes. |
Implementation: | This project will result in recommendations for the use of cement containing titanium dioxide in concrete paving mixes. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
Sulfur concrete is made from sulfur collected from the petroleum refining process and coal ash from coal burning thermal power stations. The process applies vibration and pressure to a mixture of heated sulfur and coal ash. The resulting concrete is 100 percent recycled. Hardened sulfur concrete is dense and acidresistant enough to be used where PCC cannot be used. Although most concrete pavements will not need such a high level of resistance, a feasibility study may be warranted to determine whether sulfur concrete could be used for concrete paving.
Tasks:
Benefits: | Sulfur concrete that consists of 100 percent recycled material, made from byproducts of electricity production and petroleum refinement; a dense, acidresistant material that may have applications for concrete paving. |
Products: | Recommendations for the use of sulfur concrete in paving applications. |
Implementation: | This project will result in recommendations for the use of sulfur concrete for concrete paving applications. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
One of the main problems with rehabilitating or reconstructing existing asphalt pavement is the question of what to do with the wasted RAP. Much of the time it is recycled back into a new asphalt pavement or used as embankment material. Though it has been recycled back into concrete on occasion (Austria does it regularly), its use and performance has not been widespread or documented in the United States. This research intends to determine whether RAP can be used as an aggregate in concrete pavements. The specific objectives will help determine the expected performance and potential detrimental effects of using RAP for aggregate in concrete.
Tasks:
Benefits: | RAP in concrete paving mixes, reducing the amount of RAP that must be disposed, as well as reducing the demand for virgin aggregate for concrete pavements. |
Products: | Recommendations for using RAP as an aggregate for concrete paving mixes. |
Implementation: | This project will result in recommendations, including mix design recommendations and limits for RAP properties, for using RAP as an aggregate in concrete paving mixes. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
To determine innovative ways to use recycled concrete in PCC pavements, this research will investigate the boundaries of using recycled materials in bases and two-lift construction; investigate its use in shorter performance life pavements, such as 8-year pavement; and investigate using portions of the product (i.e., fine or coarse fractions). FHWA’s program for recycled concrete should be reviewed before executing this effort.
Tasks:
Benefits: | Recycled concrete for aggregate in new concrete pavements, reducing the amount of reclaimed concrete pavement that must be disposed, as well as the demand for virgin aggregate in concrete pavements. |
Products: | Recommendations for using recycled concrete as aggregate in new pavement construction. |
Implementation: | This project will result in recommendations for using recycled concrete as aggregate in new paving mixes, including limits for usage. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $500 k-$1 M |
The use of recycled aggregate in concrete pavement is of great interest for reducing waste and reusing materials available at the job site. Using recycled aggregate will also reduce the amount of aggregate hauled to the job site. Research is needed to determine the applicability of standard tests and acceptance criteria for using recycled concrete as aggregate and PCC comprised of recycled concrete as aggregate.
Tasks:
Benefits: | Established acceptance criteria and test procedures for recycled aggregate in new concrete pavements to promote the use of recycled aggregates, thereby reducing the demand for virgin aggregate for new construction. |
Products: | Recommendations for acceptance criteria and test procedures for recycled aggregate and concrete made with recycled aggregate. |
Implementation: | This project will result in recommendations for acceptance criteria and acceptance test procedures for recycled aggregate and concrete made with recycled aggregate. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $1 M-$2 M |
Fly ash, silica fume, and blast furnace slag are three common waste products that can be used to replace or supplement cement in concrete mixtures to produce more durable, workable, higher strength concrete. However, other waste materials, such as rice husk ash, palm oil fuel ash, and other agricultural wastes, also are proving to be effective materials for use in concrete. Sludge from paper mills can be heated to form metakaolin, which can be used as an additive for concrete, producing a very impermeable product. In addition, recent studies show the benefits of using rubber particles from used tires to replace fine aggregate in PCC-based concrete used in roads.
Tasks:
Benefits: | Use of waste materials in concrete mixes, reducing the amount of waste materials and the demand for cement (which must be produced), while producing a better concrete mix. |
Products: | Recommendations (proportions and limits) for the use of waste materials in concrete paving mixes. |
Implementation: | This project will result in recommendations for the used of waste materials in concrete paving mixes, including proportions and limits. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
Ecocement replaces half of the traditional cement raw materials with ash generated by the incineration of municipal solid waste and sewage sludge. It has been recognized as type A energy efficient cement by the Japanese Institute of Civil Construction, Ministry of Construction, with the following characteristics:
During the Ecocement process, chinaware fragments in the incineration ash are used, and metal wastes are extracted and recycled. Research is needed to determine the viability of producing and using this material domestically in concrete pavements.
Tasks:
Benefits: | Ecocement that is produced during the incineration of solid waste and sewage sludge, reducing the amount of waste, while reducing the amount of cement required for concrete paving mixes, resulting in a faster setting concrete mix |
Products: | Recommendations for the production and use of Ecocement in the United States. |
Implementation: | This project will result in recommendations for producing and using Ecocement for concrete paving applications in the United States. |
Track: | 12. Advanced Concrete Pavement Materials (AM) |
Subtrack: | AM 3. Construction-Enhancing Concrete Pavement Materials |
Approximate Phasing: | N/A |
Estimated Cost: | $100 k-$250 k |
Polymer concrete consists of organic polymers, typically unsaturated polyesters that bind inorganic aggregates that essentially replace the hydraulic binders in cement with organic polymers. Polymer concrete can be used alone or as an overlay or coating on ordinary PCC to increase its durability and lifetime dramatically. Recently, investigators have studied the use of resin obtained from recycled polyethylene terephthalate (PET) bottles (water and carbonated beverage containers). Recycled PET resin-based polymer concrete is stronger and cheaper than conventional polymer concrete. Recycling PET into polymer concrete also helps dispose of waste. Research is needed to determine the viability of this material for use in concrete pavements.
Tasks:
Benefits: | Polymer concrete that results in a more durable pavement or pavement overlay, making use of recycled plastic bottles and reducing the demand on landfills. |
Products: | Recommendations for using polymer concrete for paving applications. |
Implementation: | This project will result in recommendations for using polymer concrete for concrete paving applications. |